Bitter taste receptor gene polymorphisms are an important factor in the development of nicotine dependence in African Americans

Context: Bitter sensitivity varies among individuals and ethnic groups partly due to polymorphisms in taste receptor genes (TAS2Rs). Although previous psychophysical studies suggest that taste status plays a role in nicotine dependence (ND), genetic evidence is lacking. Objectives: To determine whether single nucleotide polymorphisms (SNPs) in TAS2R16 and TAS2R38 are associated with ND and if the effects differ by sex and ethnicity. Design, setting, and participants: 2037 individuals from 602 nuclear families of African American (AA) or European American (EA) origin were recruited from the US mid-south states during 1999 -2004. Main outcome measures: ND was assessed by three measures: indexed Smoking Quantity (SQ), Heaviness of Smoking Index (HSI), and the Fagerstrom Test for Nicotine Dependence (FTND). Peripheral blood samples were obtained for DNA extraction and genotyping. Results: The TAS2R38 taster haplotype PAV was inversely associated (p= 0.0165), and the non-taster haplotype AVI was positively associated (p= 0.0120), with SQ in AA smokers. The non-taster haplotype was positively associated with all ND measures in AA female smokers (p= 0.01,0.003). No significant associations were observed in the EA sample. Conclusions: TAS2R38 polymorphisms are an important factor in determining ND in AAs. Heightened oral sensitivity confers protection against ND. Conversely, decreased sensitivity represents a risk factor for ND, especially in AA females. Together, our findings suggest that taster status plays a role in governing the development of ND and may represent a way to identify individuals at risk for developing ND, particularly in AA smokers.